From the first frames of The Unknown Woman, it’s clear that the film is a notable departure for Italian writer-director Giuseppe Tornatore. The movie begins with a sort of obscene casting call, during which groups of women, clad only in underwear and ghoulish masks, present themselves to an unseen pimp named Mold (Michele Placido) to be selected for his ring of sex slaves. Tornatore made his name with warmly nostalgic Sicilian epics like Cinema Paradiso (1988) and MaleÃ±a (2000), but this latest export, released two years ago in Italy and opened recently in New York, is one lurid piece of work.

After that chilling opener, we meet up in Italy sometime later with Irena (Xenia Rappoport), a Ukrainian and one of Mold’s chosen girls. Irena’s past has plainly ravaged her; she’s prone to graphic flashbacks of the abuse she suffered. Bent on securing employment as a maid in a particular apartment complex, Irena offers 30% of her salary to the doorman if he’ll hook her up with a job. But it’s not the building that interests her; Irena has her eye on one of the families living there. She devotes herself to infiltrating the Adacher family, married jewelers with a young daughter, with single-minded zeal, breaking into their apartment, scrutinizing their trash, and instigating the morbid demise of their nanny Gina (Piera Degli Esposti). When Irena scores her coveted position as Gina’s replacement, she forges a close bond with Tea (Clara Dossena), her small charge, who suffers from a condition that impairs her reflexes.

Irena’s shady motives make for an intriguing hook as we gradually learn what she’s really after, but Tornatore overcooks the elements from the start. He relies heavily on Ennio Morricone’s roiling score to ratchet up suspense, even when the actors alone generate ample tension. The director also can’t resist indulging his trademark sentimentality: he contrasts Irena’s excruciating memories of her days as a prostitute with idyllic reminiscences, drenched in gold light, of tender rolls in the hay with Nello, her true love.

The narrative becomes increasingly ludicrous when the sinister Mold reenters Irena’s life. After a genuinely heart-pounding climax, in which Irena’s past and present employers narrowly avoid a violent collision, the overlong movie offers a succession of preposterous twists. In the central role, Rappoport holds the proceedings together, to some extent, with her brave, committed performance. She keep us on her character’s side, even when Irena’s actions threaten to do the opposite (as when she opts for some seriously eyebrow-raising tactics in teaching Tea to protect herself when she falls). But Tornatore does his leading lady a disservice by skimping on key details (why did Irena find her way to Mold’s racket in the first place?) in favor of crass set pieces like the scene in which Irena is assaulted by two thugs wearing Santa Claus costumes. The resulting whole is a frustrating muddle, too disturbing to yield rewarding thrills and too convoluted to move us with its social message.

The film brings to mind Stephen Frears’s Dirty Pretty Things (2002), another grueling saga of an Eastern European woman trying for a fresh Western future. But Frears wisely leavened that dark story with moments of earned lightness amid the despair. The Unknown Woman is so relentless that its tortuous intensity becomes wearying. Your attention won’t wander, but you might leave with the impression that a merely life-size version of Irena’s story would have been gripping enough.